Fissure

A fissure is a long, narrow crack opening along the surface of Earth. The term is derived from the Latin word fissura, which means 'cleft' or 'crack'. Fissures emerge in Earth's crust, on ice sheets and glaciers, and on volcanoes.

Ground fissure

A ground fissure, also called an earth fissure, is a long, narrow crack or linear opening in the Earth's crust. Ground fissures can form naturally, such as from

A crevasse, also called an ice fissure, is a deep linear crack in an ice sheet or glacier resulting from the opposing force produced by their movement at different rates of speed. The force builds until their associated shear stress is sufficient to break the ice along the faces. The breakage often forms vertical or near-vertical walls, which can melt and create seracs, arches, and other ice formations.^[10] A crevasse may be as deep as 45 m (148 ft) and as wide as 20 m (66 ft).^[11] A crevasse may be covered, but not necessarily filled, by a snow bridge made of the previous years' accumulation and snow drifts. The result is that crevasses are rendered invisible, and extremely dangerous to anyone attempting to traverse a glacier.^[12]

Types of crevasses

• Longitudinal crevasses form parallel to the ice flow where the glacier width is expanding.^[13]
• Splaying crevasses appear along the edges of a glacier.
• Transverse crevasses form in a zone of longitudinal extension where the principal stresses are parallel to the direction of glacier flow.^[13]

Fissure vent

A fissure vent, also known as a volcanic fissure or eruption fissure, is a long

In the United States, about 40% of the groundwater used for drinking comes from karst aquifers.

Typical karst hydrogeology consists of a network of interconnected fissures, fractures, and conduits emplaced within permeable rock. Most of the groundwater flow occurs through a network of openings, while groundwater is held in storage within the geological structures themselves.

See also

• Fabric (geology)
• Fissure vein
• Thermokarst
• Topography

References